How do you simplify to tell whether the ratios #3/5, 5/3# form a proportion?
They are not in direct proportion.
A proportion is a statement that two ratios are equal.
Fractions can be written as ratios.
It should be obvious that these are not equal.
In a direct proportion, as one quantity increases, the other decreases.
One is a proper fraction and the other is an improper fraction.